15
"Friendships are determined by asking the participants, and hence are directed, since A may say that B is their friend but not vice versa". Dirigidos (Directed) No dirigidos (Undirected) Pesados (Weighted) 2,2 Tipos de enlaces: 1,3

17
A single gigant component that connected 52 percent (288). Moody said: They might know that their partner had a previous partner. But they dont think about the fact that this partner had a previous partner, who had a partner, and so on". The two most distant individuals are 37 steps apart.

18
No core group of very sexually active people at the high school. This network could be compared to rural phone lines, running from a long main trunk line to individual houses. As a comparison, many adult sexual networks are more like an airline hub system where many points are connected to a small number of hubs.

19
There were 63 simple pairs only 35 percent of the romantically active students (189) were involved in networks containing three or fewer students. There were very few components of intermediate size (4 to 15) students.

20
Long chains of connections. No loops: The surprising thing about the network at Jefferson High was the near absence of cycling. The lack of cycling seems traceable to rules that adolescents have about who they will not date. No to take seconds in a relationship.

33
Random graphs – Erdos & Renyi (1960) Start with N nodes and for each pair of nodes, with probability p, add a link between them. For large N, there is a giant connected component if the average connectivity (number of links per node) is larger than 1.

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Social networks: Milgrams experiment 160 letters: From Wichita (Kansas) and Omaha (Nebraska) to Sharon (Mass) Milgram, Psych Today 2, 60 (1967) who is more likely than you If you do not know the target person on a personal basis, do not try to contact him directly. Instead, mail this folder to a personal acquaintance who is more likely than you to know the target person.